1. Technical Field
The present invention relates to a guidable cutting instrument, and more particularly, to a guidable needle for use in biopsy sampling of tissue.
2. Background Information
Biopsy is the removal and study of body tissue for medical diagnosis. Typically, physicians obtain biopsy samples in order to detect tissue abnormalities, such as the presence of a cancerous growth, and/or to determine the extent to which the cancerous growth may have spread in the affected tissue. Various known biopsy instruments may be used to acquire tissue samples from different areas of interest in the body of a patient.
Biopsy instruments often comprise a two-part needle assembly comprising a stylet and cannula. One example of a conventional biopsy instrument is the QUICK-CORE® Biopsy Needle, available from Cook Incorporated, of Bloomington, Ind. The QUICK-CORE® needle 100 is shown in FIGS. 1-1A. Needle 100 includes a stylet 110 and an outer cannula 120 enclosing the stylet. Stylet 110 has a tissue collecting or specimen notch 115 formed near the distal end of the stylet. Cannula 120 has a sharpened point 124 at its distal end. The stylet 110 and the cannula 120 are arranged so that the cannula point 124 is advanceable over the stylet 110 in order to cover the specimen notch 115.
Two-part biopsy needles having respective inner and outer members, such as stylet 110 and cannula 120, are now well-known in the medical community. In use, such needles may be activated by a spring-loaded handle 150 of a type disclosed, e.g., in U.S. Pat. No. 5,538,010. Activation of the spring-loaded handle 150 causes rapid forward movement of the cannula 120 over the stylet 110, and in particular, over the stylet notch 115. This action severs a specimen of the prolapsed tissue into which the needle has been inserted, which specimen becomes retained in the specimen notch 115 of the stylet 110. Once the biopsy needle 100 is withdrawn, the cannula is retracted, and the tissue sample may be recovered from the stylet for further examination.
This prior art needle assembly works very well for a variety of biopsy procedures. However, the ability of the needle to negotiate through curves in the vasculature, and particularly, the ability of the needle to avoid body structures and organs situated in the path of the needle, is limited. As a result, use of the prior art assembly is generally limited to a “straight shot” type of procedure, in which the needle is inserted percutaneously and directly advanced in generally linear fashion to a target lesion that is accessible without significant obstruction.
In recent years, techniques for medical imagery have improved to an extent that physicians are now able to clearly view the positioning of a medical interventional device as it advances along a designated pathway within the body of a patient. Newer imaging techniques are capable of providing detail that is superior to that provided by many classical techniques, such as x-ray. For example, medical ultrasonography enables the physician to view a sonogram in real time that clearly shows the position of a device, such as a needle, as it advances through the body. This ability to view the position of a medical device within the body of a patient in real time provides the physician with the opportunity to manipulate the position of the device as it navigates the designated pathway. However, “straight shot” type devices are in large part incapable of being steered, navigated, or otherwise bended around a body organ or other obstruction that may be encountered within the body of the patient.
It would be desirable to provide a cutting device, such as a biopsy tissue-sampling needle, that is capable of effectively negotiating around body organs or other obstructions in the body of a patient. It would also be desirable to provide a cutting instrument of relatively simple design that enables the physician to obtain a tissue sample from a remote target site within the body of the patient in a manner that does not require passing the cutting instrument through obstructions that may be encountered along the pathway.